Safety and efficiency assessment of absorber with an initial offset in a parabolic trough collector

The non-uniform solar flux distribution on the absorber surface in a parabolic trough collector results in a large temperature gradient and stress, thus leading to safety hazards. This study proposed a installation mode of the absorber in a parabolic trough collector, with an initial offset. The geometric centre of the absorber deviates from the focal line by an initial offset to increase the uniformity of the solar flux distribution and reduce the stress on the absorber surface, without incurring an additional cost. A mechanism model of the parabolic trough collector was established, and a theoretical equation for the critical initial offset was derived. Moreover, an optical-thermal-fluid-structural multiphysics coupled model of the system was developed via the software COMSOL to study the system performance with an absorber having an initial offset. The simulation results indicated that the absorber with an initial offset of-24 mm significantly decreased the circumferential temperature difference and maximum stress of the absorber by up to 45% and 39.5%, respectively, and the optical-thermal efficiency is slightly increased by 2.5%, in comparison with that without an initial offset.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This study proposes an installation mode for the absorber in a parabolic trough collector to increase the uniformity of solar flux distribution and reduce stress. The simulation results show that with an initial offset, the temperature difference and stress of the absorber are significantly decreased, while the optical-thermal efficiency is slightly increased.